Cellular telephones have been designed to be smaller to reduce the size and weight to be easier to hold and carry. One result of the smaller size, however, is that the microphone is farther from the user's mouth, which makes it more difficult for the microphone to pick up the user's voice.
The flip, the pivotable portion that covers the keypad and flips open when the telephone is in use, has been used to help overcome this problem, but with mixed results. One approach has been to place the microphone at the free end of the flip. This approach, however, requires that wires be run to the microphone, which adds cost and manufacturing steps. In addition, the wires must be routed across the hinge, or an electrical connection must be incorporated in the hinge. This also adds cost, and creates other problems with the connections or wires wearing or breaking after repeated use. In addition, connections at the hinge can create substantial acoustic interference and/or distortion.
Another approach has been to build an acoustic wave guide into the flip. The wave guide is a triangular shaped cavity formed between panels in the flip that funnels sound to the hinge. An opening in the hinge directs the sound to the microphone. This approach requires that the flip be made thicker to accommodate the wave guide, which increases the thickness of the telephone itself, and diminishes its aesthetic appeal.
The present invention provides a solution to the problem of guiding voice sound to the microphone in a flip style cellular telephone that eliminates the disadvantages in the art.
According to the present invention, a flip style cellular telephone includes a main housing and a flip mounted to the main housing by a hinge. The flip has an acoustic pipe, a hollow sound-carrying channel, that extends on a peripheral edge of the flip from the free end to the hinged end to carry sound from the free end, which is positioned near the user's mouth, to the hinged end, near where the microphone is located.
The location of the acoustic pipe on the peripheral edges of the flip advantageously positions the additional thickness on the periphery of the flip, so that the portion of the flip that covers the key pad remains thin, and the profile of the unit as a whole is aesthetically pleasing. The main housing of the telephone can be shaped to accommodate the acoustic pipe when the flip is in the closed position to maintain the thin profile of the telephone.
A microphone is mounted in the main housing. The microphone is in acoustic communication with the acoustic pipe to receive sound from the acoustic pipe. Preferably, the hinge is hollow and the acoustic pipe connects to the microphone through the hollow hinge.
The acoustic pipe may extend along one side of the flip, or preferably, the acoustic pipe extends along the entire surrounding peripheral edge of the flip. A portion of the acoustic pipe may be formed as a closed cavity to tune a remaining portion that connects with the microphone.
According to another aspect of the invention, the acoustic pipe has openings at the free end of the flip for sound entry. The openings are preferably formed as slots in a central portion of the free end.